Model rocket-glider



J. F. SCHUTZ ETAL Nov. 24, 1964 MODEL ROCKET-GLIDER 2 Sheets-Sheet 1 Filed July 23, 1962 Fig. 2

ATTORNEY s 0 L mz OW M mm Z W5 O HE f V m wmP United States Patent 3,157,960 I MODEL ROCKET-GLEDER John F. Schlitz, Canon i-Zity, and Verizon 1). Estes, Penrose, Colo assig'i ofs to Estes Industries, Inc, a corporation erosionue V p 7 Filed July 23, 1962, Ser. N0. 211,560 iZllaimS. (6]. 46-81) This invention relates to model aircraft and more particularly to jet-driven model aircraft, it being a primary object of the invention to provide a novel and improved jet-driven model which is adapted to ascend to a substantial height in a manner which will simulate the flight of a rocket and to then descend by soaring and gliding in Wide arcs and for substantial distances in a manner which will simulate the flight ofa glider. As such, the invention will be hereinafter referred to as a model rocket-glider or simply as a rocket-glider.-

Another object of the invention is to provide a novel and improved jet driven model rocket-glider having a shiftable arrangement of its aerodynamic controls Whereby to permit a direct and efiicient upward flight as a jetdriven model rocket to a substantial height and then, as it reaches its maximum altitude of flight, to tip horizontally and to soar and to glide along a straight course or preferably in widespirals as it returns to the earth.

Another object of the invention is to provide a novel and improved model rocket gliderwhich is adapted to receive, hold and use a conventional cylindrical jet motor unit of a type commonly available for driving model rockets.

Another object of the invention is to provide a novel and improved rocket glider which uses a model rocket jet motor of acornmon type which is adapted to eject itself after the driving charge is burned out and which provides an improved, shiftable control means operable to permit the unit to be projected upwardly as a rocket to reach a maximum altitude of flight and then to tip horizontally and glide, with the conirol means being actuated from one setting to another setting by the ejection action of the model rocket jet motor.

Further objects of the inventionare to provide a novel and improved model rocket glider which is a simple, safe, inexpensive, easily-built, neat-appearing, reliable and rugged unit capable of being used for many repeated flights. I j 7 With the foregoing and other objects in vievv, all of which m'ore fully hereinafter appear, our invention comprises certain novel and improved constructions, com- A binations and arrangements" of parts of elements as hereinafter dscrihd, defined in the appended claims, and illustrated inpreferr'ed embodiment in the a'coompanying drawing in which: 1

FIGURE 1 is a lan view or a model rocket glider or a type which is especially adapted to be constructed according to the principles of our invention, and which is similar in appearance to certain of high-speed, prototype aircraft. j

FIGURE 2 is a right elevationalview of the model rocket glider illustrated at FIGURE 1.

FIGURE 3 is a rear-endel'e'vati-onal View of the model rocket-glider illustrated at FIGURE 1.

FIGURE 4 is alongitudiiial sectional elevational view as taken from the indicated line 4-4 at FIG. 1 but on an enlarged scale, the view illustrating a model rocket motor as be'ing'in place in position for upward'flight.

FIGURE 5 is a real-portion of the longitudinal se'ctional elevational View illustrated at FIGURE 4 but With out the model rocket motor being in place to indicate a shifting in position of the control varies as when the motor is ejected.

FIGURE 6 is an auxiliary rear View of the model 35,157,960 Patented Nov. 24, 1964 rocket glider, as looking downwardly upon the model in the direction of the indicated arrow 6 at FIG. 2, but Without therocket motorbeing in position and with the flight controls at each side of the model being shifted to selected positions to illustrate the manner of their movement.

FIGURE'7 is a fragmentary sectional detail as taken from the indicated line 7-7 at FIG. 1 but on a greatly enlarged scale. I

FIGURE 8' is a transverse sectional detail as taken from the indicated line 88 at FIG. 4, but on an enlarged scale. g p I FIGURE 9 is a longitudinal sectional view of a rocket motor of a type which is especially adapted to be used with the rnodel glider.

FIGURE 10 is a schematic view, on a greatly reduced scale, to indicate the nature of the flight path of the rocket glider as it is being lofted, with spiralled broken lines indicating the rotation of the model at its wing tips and another broken line indicating the soaring nature of the flight as the model descends to the earth.

Possibly because or the nations activity in firing rockets of various types and in flying experimental high-speed jet planes, there has de veloped an extensive activity in the construction and flying of model rockets, to the point that afNational Association of Rocketry has been organized to promote safety codes and standardize model rocket sizes and the critical components such as the rocket motors. Accordingly, comparatively safe but efficient high-thrust model rocket motors have been developed which are formed asstandardized cylindrical units approximately /s-inch in diameter and 2'%-inches long. These motor s developsuflicient power to drive a lightweight model rooket as: high as 1000 feet or more.

The problem of returning a model rocket to earth has received considerable attention. Even though these models are" made as light as possible, a properly balanced model rocket, if not arrested in its flight or the nature of its flight changed in some manner after it reaches maximum altitude, will act very much like an arrow and will over to fall to' the earth point first and gain considerable velocity before striking the earth. Unchecked, a model rocket may strike the earth so hard as to destroy itself onto" cause a serious injury if it hits a person. To avoid this possibility, the standardized model roclge't motors include a small explosive ejection charge at their froi t end which is fired after the driving charge of the model rocket engine is burnt out. This ejection charge may us used to open a parachute, to eject the motor fromthe model rocket and change the balance of the unit or to blow the model rocket into two sections which may tumble to the earth in an irregular manner and at considerably reduced velocities.

The present invention was conceived and developed to provide an improved manner of returning a model rocket to earth, and contemplates the construction of the model rocket glider which advantageously uses a standard model rocket motor to control the guiding vanes of the model in such a anner that the model will be aerodynamically balanced when the motor is installed to fly as rocket and after the rocket motor is ejected from the model; it will be balanced tofly as a glider.

Referring more particularly to the drawing, the model rocket; is illustrated as simulating a backswept-wing type aircraft which combines the ordinary wing and tail functions into a single unit and" replaces conventional tail elevators and wing ailerons by a single flap on each wing, which will be liereinafter referred to as an elevato'r. However, it is to be pointed out that the rinciples of the inventiomwhile described with reference to this special embodiment can be applied to models slightly greater than the diameter of a standard cylindrical rocket motor M so that the motor may fit into this tube with a'loose freely-sliding fit. The front end of the body is closed by a tapering nose cone 12 of balsa or any similar lightweight material. The base of this cone is of the same diameter as the external diameter ofthe tubular body, but with ai sh ortreduced-diameter shoulder portion 13 extending therebeyond and being adapted to permanently fit into the tube. .A pocket 14 or like cavity may be formed in the body of this cone to hold a counterweight 15 which facilitates the balancing of the unit when it is in flight.

A pair of backswept Wings 16 is affixed to the under edge of the body 11 to outstand laterally therefrom, at

a slight upward inclination when viewed from the front or rear of the unit and at a selected backsweep when viewed in plan, and the wings are proportioned to give the model a good aerodynamic balance. These wings are preferably made ofbalsa wood or similar light- Weight material. Following standard model construction, they may be glued to the underside of the body I 11 and are suitably reinforced atthis glued section by a, pair of longitudinally-disposed reinforcing strips 17 which abut underneath adjoining edges of the wings at the longitudinal center of the unit. These strips 17 extend beyond the trailing edges of the wings to form elevon stops as hereinafter described.

To complete the general arrangement of this model, a landing skid 18 of lightweight material such as balsa depends from the front end of the reinforcing strips at a proper position for striking the ground surface when the model lands as at the completion of a glide. A simple launching tube 19 of rigid paper to appear somewhat as an oversized straw is affixed to the top of the body 11 near the trailing edge thereof and it is contemplated that the model may be placed upon a common type of a simple launching stand which includes an upright rigid wire which serves as a launching guide.

The guiding means associated with the wings of this model rocket include fixed stabilizers 20, fixed spin tabs 21 at the outer end of each stabilizer and adjustable elevator 22. The outer edge of each wing lies in spaced parallelism with the longitudinal axis of body and a flat upright stabilizer 20 is aflixed to each outer wing section. The spin tabs 21 are formed. as comparatively ,narrow flatmembers which outstand from the outer side of each stabilizer 20. These tabs are placed at selected opposing inclinations adapted to initiate a rotation of the model about the longitudinal axis of the body when itis being projected upwardly as a rocket as hereinafter described.

of the wing sections by hinge strips 23; the hinge strips being of thin, pliable, adhesive-coated cloth or plastic material which mayv be quickly and easily atfixed onto the trailing portion of the upper surface of the wing 16 and onto the upper surface of the elevons 22 along this connecting edge. This permits the elevons to be easily turned upwardly and the unit is designed to be balanced, as by use of the counter-weight 15, to glide when the elevons are tilted upwardly somewhat. It is contemplated that each elevator will be adjusted somewhat differently from the other -to counteract the spin action of the tabs 21 and to cause the model to fly along a straight course or to fly in a-selected arcuate course.

Each elevator is urged upwardly by a pull string 24,

which is a lightweight rubber band. A single band serves to pull both elevators upwardly by having each end connected to the trailing edge of an elevator, as at connection point 25, and with the length of the band being sufiicient to permit it to be looped over the front end of the launching tube 19 under moderate tension.

An adjustablestop means is formed at each side of 'tactsanelevator. To provide for simple construction, a

tab 25 is preferably formed of a reinforced balsa strip and the socket 27 is a passageway through the soft, resilient wood which forms a natural socket which threads itself to receive the adjusting screw 28 with a snug firm grip. Accordingly, the upward movement of each elevator is limited by the setting of the adjusting screw. The elevator, unless otherwise restricted, will normally move upwardly until it strikes the bottom of,

the adjusting screw 28.

The desirable arrangement of each elevator is such that its trailing edge is at the trailing edge of the body tube 11. Also, since each elevator extends inwardly to a point close to the longitudinal center of the unit, a notched recess 29 is cut into the body at the underside of the trailing edge with the notch being proportioned to permit the elevators to defiect upwardly and thereinto. It is to be noted that the downward limit of the movement of the elevators is restricted by a rearward extension of the re inforcing strips. 17, and when they rest upon the strips, the elevators are substantially in alignment with the plane surfaces of the wings v It is immediately apparent that the elevators 22 must be depressed to this downward position and out of the notched recess 29 whenever the rocket motor M is iii stalled in the model by inserting it into the rear portion of the body tube 11 for the side of the motor will press against the elevators. To push the elevators against the ends of the strip 17 in alignment with the plane of the wing surfaces, a spacer formed as a tab 30 upstands from the upper surface of each elevator adjacent to its inner edge. Thus, the pressing of the elevators against the motor serves a double function for the motor sets the elevators for rocket flight and at the same time the pull of the string 24 urging each elevator upwardly serves to hold the motor in place within the tubular body 11 with a light pressure sufiicient to prevent the motor from falling out of the body accidentally.

To complete the unit, a plug 31 is mounted in the tubular bodynear the center portion thereof and at a position which permits the motor to be inserted into the body to a point where the trailing end of the motor is at the trail ing edge of the body, as clearly illustrated at FIG. 4. v

The rocket motor M consists of an outer shell 32 of rigid cardboard or like material. A, refractory nozzle 33 is positioned within this shell at its discharge end. A compressed driving charge of powder 34- commences at a point adjacent to the nozzle and fills a greater portion of the tubular shell. Near the leading end of the shell the powder charge terminates and a slow burning, delay charge 35 is pushed against the end of the powder charge. The unit is completed by a small explosive charge 36 at the' leading end of the model. This motor is ignited at the nozzle 33 by lighting a fuse 37 placed in the nozzle or by the use of a conventional type of ignition wire, not shown, which may be used in lieu of the fuse 37.

In using the present invention, the model rocket glider is first tested by trial glides without a rocket motor, to

permit the elevons 22 to be properly set by the adjusting screws 28. When the model glides in a desirable maninto the body 11. The model is placed upon an ordinary launching pad with the longitudinal axis thereof being in a vertical or near vertical position. Next, the engine is ignited by lighting the fuse 37, or by electrical means, not shown, and the driving charged-4 of powder commences to burn ejecting a high-velocity jet rearwardly of the model. This driving charge lofts the model rocket upwardly at high velocity and during this portion of the flight the spin tabs 21 cause the rocket to rotate, as in the manner illustrated diagrammatically at FIG. 10. When the driving charge burns out, the delay charge burns for a while to permit the model rocket to continue to coast upwardly and decelerate. Next, the small explosive charge 36 ignites ejecting the rocket motor. When the motor is ejected, the elevators 22 move upwardly to the gliding position as determined by the adjusting screws 23. Thence, the rocket begins a downward glide. Usually it is desirable to set the elevators in such a manner as to cause the model to glide in arcs rather than on a straight course to facilitate recovery of the rocket without having to travel too far from the launching site.

While we have now described our invention in considerable detail, it is obvious that others skilled in the art can devise and build alternate and equivalent constructions; for example, an airplane having a wing tail arrangement so that the elevators of the ail may be arranged to function to change their adjustment when the rocket motor is blown out of the body of the model. Hence, we desire that our constructions be limited not to the constructions illustrated and described but only by the proper scope of the appended claims.

We claim:

1. A model rocket-glider adapted to be propelled by a model rocket motor having a pyro-propulsion charge adapted to be jetted from the trailing end thereof and an e ection charge adapted to flare from the leading end thereof after the propulsion charge burns out, and comprising, in combination therewith:

(a) a longitudinally extended body section,

(b) a socket associated with the body adapted to recelve and hold the rocket motor,

(0) an adjustable airfoil means adapted to be shifted to a first position to render the model suitable for fllght as a rocket and to be shifted to a second position to render the model suitable for flight as a glider, 1

(d) a shiftable airfoil holding means adjacent to the socket associated with the rocket motor within the socket and adapted to be set at a holding position to hold the airfoil means at its said first position and to be shifted responsive to the burning of the e egtlon charge to thereupon release the airfoil means; an

(e) an airfoil shifting means adapted to urge and to hold the airfoil means towards and at its said second position whenever it is released by the said holding means,

whereby, with the motor within the socket, the rocketglider is set to fly as a rocket, as during the burning of the propulsive charge and upon the subsequent burning of the ejection charge the rocket-glider is set to fly as a glider.

2. A model rocket-glider adapted to be propelled by a model rocket motor having a pyro-propulsion charge adapted to be jetted from the trailing end thereof and an ejection charge adapted to flare from the leading end thereof after the propulsion charge burns out, and comprising in combination therewith,

(a) a longitudinally extended body section,

(b) a substantially closed socket in the body havin an opening at the trailing end thereof and being adapted to slidably receive and hold the rocket motor and to permit the motor to be ejected rearwardly upon the burning of the ejection charge,

(0) shiftable airfoil means adapted tobe set at a first position to render the model suitable for flight as a rocket and to be shifted to a second position to render the model suitable for flight as a glider,

(d) an airfoil holding means adjacent to the socket adapted to engage the rocket motor within the socket and to thereby be shifted to a holding position to hold the airfoil means at its said first position and being adapted to shift from its engagement with the rocket, responsive to ejection of the motor, to a releasing position to release the airfoil means; and,

(e) an airfoil shifting means adapted to urge and hold the airfoil means towards and at the said second position whenever it is released by the said holding means,

whereby, with the motor within the socket, the rocketglider is set to fly as a rocket, as during the burning of the propulsive charge, and upon the subsequent ejection of the motor by burning of the ejection charge, the rocketglider is set to fly as a glider.

3. In the organization defined in claim 2 wherein the airfoil holding means includes a detent adjacent to the socket and adapted to bear against the side of the model rocket motor when it is inserted into the socket, to hold the airfoil means in the said first position, said detent being adapted to move into the socket when the rocket motor is ejected to said releasing position to permit the ai foil means to shift to the second said position whenever the rocket motor is ejected from the socket.

4. In the organization set forth in claim 2, including fixed airfoil sections adapted to support the shiftable airfoil means, with the shiftable airfoil means being hingedly mounted onto the fixed airfoil means, said shiftable airfoil means including a wing elevator unit at each side of the body with the inner end of each elevator being adjacent to the socket and a detent at the inner end of each wing elevator unit adapted to press against the side of the model rocket motor when the airfoil means are at the first said position and'to move into the cavity of the socket when at the second set position.

5. A model rocket-glider adapted to be propelled by a cylindrical model rocket motor having a pyro-propulsion charge adapted to be jetted from its trailing end and an ejection charge adapted to flare from its leading end after the propulsion charge burns out, and comprising, in combination therewith,

(a) a longitudinally-extended, tubuiar body having the trailing end open to form a socket adapted to receive the model rocket motor with the trailing end of the motor being near the trailing end of the body,

(b) a pair of outstanding wing members adapted to sustain the model in flight,

(c) a pocket-like opening in the wall of the body adjacent to and rearwardly of the trailing edge of each Wing member,

(d) an elevator flap hingedly affixed to the trailing edge of each wing with the inner end of each elevator flap extending into said pocket, said elevators being adapted to control the flight of the model and being adapted to be set at a first position to render the model suitable for flight as a rocket when the motor is in position in the socket and is operating, and to be set at a second position to render the model suitable for flight as a glider after the motor is ejected from the socket by burning of the ejection charge,

(2) a resilient means connected to the elevators adapted to urge and to normally hold the elevators at the said second position, and

(f) a tab at the inward end of each elevator extending into the socket and being adapted to be deflected to the side of the socket when the motor is inserted therein with the elevators being in said first position when the tabs are thus deflected.

6. In the organization set forth in claim 5, wherein said resilient means comprise rubber bands at the edges of the elevators adapted to pull them upwardly and adjustable stops above the elevators adapted to limit the upward movement to the said second position.

7. In the organization set forth in claim 5', including spin tabs at the outer edges of each Wing adapted to cause the unit to spiral in an upward jet-driven flight 8. In the organization "defined in. claim 5, including flight stabilizer fins at the outer edge of each wing and spin tabs at the outer face of each stabilizer fin adapted to cause the unit to'spiral in an upward, jet-driven flight.

References Cited in the file of this patent UNITED STATE PAIENTS Orkin Apr. 1 6 1-946 FOREIGN PATENTS Ge rmany Feb. 1', 1954 Great Britain July 2 8, I954 

1. A MODEL ROCKET-GLIDER ADAPTED TO BE PROPELLED BY A MODEL ROCKET MOTOR HAVING A PYRO-PROPULSION CHARGE ADAPTED TO BE JETTED FROM THE TRAILING END THEREOF AND AN EJECTION CHARGE ADAPTED TO FLARE FROM THE LEADING END THEREOF AFTER THE PROPULSION CHARGE BURNS OUT, AND COMPRISING, IN COMBINATION THEREWITH: (A) A LONGITUDINALLY EXTENDED BODY SECTION, (B) A SOCKET ASSOCIATED WITH THE BODY ADAPTED TO RECEIVE AND HOLD THE ROCKET MOTOR, (C) AN ADJUSTABLE AIRFOIL MEANS ADAPTED TO BE SHIFTED TO A FIRST POSITION TO RENDER THE MODEL SUITABLE FOR FLIGHT AS A ROCKET AND TO BE SHIFTED TO A SECOND POSITION TO RENDER THE MODEL SUITABLE FOR FLIGHT AS A GLIDER, (D) A SHIFTABLE AIRFOIL HOLDING MEANS ADJACENT TO THE SOCKET ASSOCIATED WITH THE ROCKET MOTOR WITHIN THE SOCKET AND ADAPTED TO BE SET AT A HOLDING POSITION TO HOLD THE AIRFOIL MEANS AT ITS SAID FIRST POSITION AND TO BE SHIFTED RESPONSIVE TO THE BURNING OF THE EJECTION CHARGE TO THEREUPON RELEASE THE AIRFOIL MEANS; AND, (E) AN AIRFOIL SHIFTING MEANS ADAPTED TO URGE AND TO HOLD THE AIRFOIL MEANS TOWARDS AND AT ITS SAID SECOND POSITION WHENEVER IT IS RELEASED BY THE SAID HOLDING MEANS, WHEREBY, WITH THE MOTOR WITHIN THE SOCKET, THE ROCKETGLIDER IS SET TO FLY AS A ROCKET, AS DURING THE BURNING OF THE PROPULSIVE CHARGE AND UPON THE SUBSEQUENT BURNING OF THE EJECTION CHARGE THE ROCKET-GLIDER IS SET TO FLY AS A GLIDER. 